Rapid-quench heat-treating oven



Feb. 15, 1944. l v A Fox I 2,341,766

RAPID-QUENCH HEATTREATING OVEN VFiled Dec. l2, 1941 y 3 Sheets-Sheet l LA t/g Snventor Bg @MM2/@ql W Gttomegs V. A. FOX

RAPID-QUENCH HEAT-TREATING OVEN Feb. 15, 1944.

Filed Dec. l2, 1941 5 Sheets-Sheet 2 3nventor Vey/'8 x .Aww

Bg @aw/@Q4 Gttor'negs Feb. 15, 1944. v. A. FCX

RAPID-QUENCH HEAT-HEATING ovEN 5 sheets-Sheet s Filed Deo. 12, 1941 Gttornegs UNITED Patented Feb. 15, 1944 Vernie A. Fox, Detroit, Mich.V Application December `12, 1941, serial No.' 422,816

' s claims. l(ci. 26e-.4)

This invention relates to heat-treating ovens and, in particular, to such ovens `havingquenching means associated therewith.

One object of this invention is to provide an inverted heat-treatingoven into which the `work to be treated is inserted and withdrawnfrom Another object. of this'iri'vention-V is to provide `an invertedf'lieat-treating oven' havingquenching -means arranged beneath it so 'that the workmay be immediatelyquenched after it is. heat-'treated oven .according to a preferred embodiment of the present invention.

Fig. 2 is a cross-section along the zig-zag Vline 2`2 in Fig. l. y

Fig. 3' is a top-plan view of the rapid Iheat-treating oven shown in Figs. 1 and 2.

Fig. `tv is a horizontal section taken along the line .4-4 inFig. l atapproximately the vbottom of the oven. t

`without serious loss ot'heat or changeiofproperties or the material being treated. Another-...Objectis to provide an inverted .heattreating'oven arranged-above aspraystation below which is aquenchingstationg'so that the work may be raised intothe'oven fromv-belowfand dropped either tovthef-spraystation or toi =the quenching station-after heat"treatment,l thereby providing for either spray-cooling.,v or plunge-4o elevator cage, is subjected to heat treatment for quenching, or both.v Y v Another object is .to 4provide an invertedjheatf treating oven, having movable-'closuresv at the bottom thereof and acase movableupintoand '25 vpit. Quenching may thus be. accomplished either fby spraying, by plunging the work into the liquid down from the oven in synchronism' with'th'e doors, thereby conserving heat within the oven.

,Another object is to providean inverted heattreating oven mountedover a quenching'pit or'v with the bottom doors, whicliopen and close in timed relationship therewith. land after heat treatment the doors again yopen'and close as the elevator cage moves quickly downward into the 55 Another obiect is to provide an inverted heatquenching pit or "tank,

treating oven as set forth vin the preceding ob ject wherein a spray cooling station Vis vinterposed between the heat-treating oven and the quenching pit, so that the work maybe quenched either by applying'or by plunging, or'by a vcombination of both.

Another object isto provide an l treating oven located above a quenching pit and having an elevator operating in synchronism with v the oven doors in such a manner that the heatl is conserved within the oven by the doors and the tank and having movable bottom doors, the sys,- v tem'being so arranged that an elevator cage car.- ries thework up into the oven in synchronism v inverted vheat- General arrangement Ingeneral, the rapid-quench'"heat-treating o'ven of this invention consists ot an inverted oven mounted on an elevated frame-above a spray booth, beneath which is .located a quenchini;v pit. The bottom of the inverted oven is .closed by `a'pair of movable doors whichare operated in synchronismwith an elevator cage. The latter is moved upward into the oven in synchronism lwith the opening and closing of the doors, so that the work, which is arranged within a ycar in the the desired period of time.

' :After the heat treatment has been concluded, Vthecloors again open toLpermit the elevator cage to dropthrough a-spray booth into the quenching in the pit, or by a combination of ,both.

Htherto it has been very diil'icult to subject I relatively thin or delicate metal structures to heat foundby tests that the lapse of only three or four seconds between heat treatment and quenching frequently alters the crystalline structure of the metal to a serious extent. This is especially true in the heat treatment of airplane parts, which are constructed of light-weight metal alloys which are peculiarly sensitive to heat changes, especially in the thin structures in which they are so frequently used. For example, it hasbeen found in the cross-bracing structure of airplane wings which are welded together that the metal structure in the vicinity of the welds is quite different from the metal structurey elsewhere unless the entire structure is subjected to a careful heat treatment, which may extend as high as 900 degrees F. filter such heattreat-l ment,V aluminum alloys, especially'in sheet form,

must be quenched quicklyfwithin a few seconds` or a serious change in crystalline structure occurs. For some classes o! work, spray-quenching is fairly satisfactory but for other types of work, plunge-quenching is preferable. It is also found quench that still other types of work are preferably quenched by a combination of both sprayquenching and plunge-quenching.

Referring to the drawings by general designations (Fig. 2) the rapid-quench heat-treating oven of this invention in its' preferred form consists of an elevated framework mounted on the building oor and supporting an inverted elevated oven I2 above a spray-booth I3. Beneath the spray booth I3 is located a quenchingpit |4 containing a quenching liquid. An elevator cage |5.containing a work-carrying car I8 is moved, as desired, between the oven I2, the spray booth I3 and the quenching pit I4.

Heat-treating oven construction Referring to the drawings in detail, Fig. 1 shows the elevated and inverted oven I2 as mounted upon the elevated framework I0. The latter consists of uprights |1 interconnected by longitudinal horizontal channel members I8 and horizontal cross members |9 (Fig. 2).

Supported upon the cross members |9 are upper longitudinal and cross members 20 and 2| respectively. These serve to support the outer oven frame uprights 22 which in turn support the longitudinal and cross top frame members 23 and 24 respectively. (Figs. 1 and 2.) The outer oven side walls 25 are arranged adjacent the outer oven frame uprights 22, and are separated by an insulating layer 26 from the inner oven side walls 21. Associated respectively with these side walls are outer and inner end walls 28 and 29 respectively (Fig. 1) and outer and inner top wallsV 30 and 3| respectively. These walls define a heat-treating chamber 32 having an open bottom aperture 33 which is closed by horif zontally slidable doors 34. The latter are hol- .cylinders 43. The latter are preferably operated by pneumatic pressure, and are provided with conduits 44 and 45 at their opposite ends for the admission and discharge of fluid for operating the pistons 42 to open or close the doors 34. The admission and discharge of fluid through the conduits 44 and 45- is controlled byA magnetically operated valves (not shown), which in turn are controlled by an electric circuit containing limit switches, which are actuated in response to the upward and downward motion of the elevator cage I5.

Mounted on and movable with the bottom doors 34 are spray pipes` 46 which are secured to brackets 41 beneath the doors 34 and connected by flexible conduits 48 (Figs. 2 and 4) to the liquid supply conduits 49 extending longitudinally adjacent the longitudinal frame members I8 and supported upon brackets 50 secured to the undersides thereof. The cylinders 43 are similarly supported upon angle brackets I secured to the sides of the cross members I9 (Fig. 4)

Secured to the inner walls 21 of the oven I2 near the bottom thereof are inwardly extending brackets 52 (Fig. 2) which support the lower edges of partitions 53 which extend upward and are secured by the angle members 54 to the inner top wall 3|. The partitions 53 are thus spaced apart from the inner walls 21 and form heating chambers 55 containing heating elements 56 secured by the brackets 51 and posts 58 to the inner walls 21. The heating elements 56 are preferably electrical and connected to a source ofv electric current (not shown).

Opening out of the heating chambers 55 are ports 59'connected to inlet conduits 60 leading to the intake of an exhaust fan or blower 6| containing a blade or vane assembly 62 mounted on a shaft 63 (Fig. 1) within a casing 64. The

' shaft 63 is supported upon a bearing bracket 65 andconnected by a coupling 66 to the shaft member 69. The latter rests upon the longitudinal frame members 23. The blower 6| discharges into an outlet duct 10 which passes downwardly through a port 1| into the oven chamber 32 where it divides into oppositely extending branches 12 (Fig. 1) having discharge ports 13 disposed in the lower wall thereof.

Elevator construction I The elevator cage I5 consists of a frame work formed of longitudinal members 14 interconnected by cross members 15 and having uprights 16 extending therebetween. Rails 11 are mounted upon the cross members 15 and are of channel cross section for supporting and guiding the wheels 18 mounted upon the axles 19 of the cars I6. Brackets extend downwardly from the bottom 8| of the car I6.

The cars I6, of which there may be one or more (two being shown in Fig. 1), are interconnected by coupling members 82. and 83 joined by a coupling pin 84. The cars I6 are provided with sides 85, ends 86 and tops 81 composed partly. of netting.

Connected` as at 88 to two of the cross members 15 are cables 89 which pass through apertures 90 and 9| in the conduits 12 and oven walls 25, 21, thence over pulleys 92 (Fig. 3) mounted upon axles 93 supported in bearing bracketsv 94 mounted upon the cross members 24. Beyond these the cables 89 travel laterally and pass over pulleys 95 mounted upon a common shaft 96 supported in bearing brackets 91 like-- wise mounted upon the cross members 24. Beyond the pulleys 95 the cables 89 proceed downwardly to counterweights 98 which are received within pits 99 sunk below the floor II (Fig. 2).

Also mounted upon the shaft 96 is a drum |08 to which is connected a cable |0|. wound around the drum |00 and extends downwardly around pulleys |02 and |03 (Figs. 1 and 4) and is connected'to an eye |04 in the end of a piston rod |05, secured to a piston |06 reciprocable within a cylinder |01 actuated by pressure fluid reaching it through the conduits |08 or |09 (Fic. 4). The pulleys I 02 and |03 are supported in bearing brackets ||0 and I| respectively, whereas the cylinder |01 is supported by angle brackets ||2. The brackets I|| and ||2 are mounted upon one of the longitudinal frame members |8\-(F|g. 4). The elevator operating cylinder |01, like the door-operating cylinders 43, is operated by pressure fluid, such as by compressed air or by hydraulic pressure.

Spray booth and quenching pit construction The spray booth |3 consists of angle brackets H3, mounted on the frame uprights |1 and supporting the bent side plates ||4, the side por- The latter is tions I I of which carry members .I I5 upon which are mounted the spray pipes ||1` interconnected by vertical conduits II8 which in turn are connected to the 4liquid supply pipes IIII (Fig. 2). The lower portions |20 of the side plates I|4 are bent at right angles to the side portions |I5 and rest upon the floor II over the quenching pit I4.

The quenching pit I4 extends downwardly below the floor level II and is provided with side walls I2I, end walls |22 and a bottom wall |23. The pit I4 thus formed is lled t0 a suitable level with aliquid |24, such as water Operation In. the operation of the rapid-quench heattreating oven of this invention, the work pieces are loaded into the vcars I6, which may be outside the frame structure I0, either to the right or to the left thereof (Fig. 1). The work pieces Fig. 2, the wheels 18 running upon the tracks 11. .y Meanwhile the heating elements 55 have been' energized, and the blower 5| operated to circulate the thus-heated air through the oven chamber 32 in the circuit indicated by the arrows (Figs.

Noptionally be halted in this position. For delicate work pieces, or those constructed of sensi-v tive metals or alloys, however, it is usually preferable not to halt the elevator I5 Within the spray booth I3, but instead to lower it unchecked into the quenching pit I4. When the elevator I5 plunges into the liquid |24 in the quenching pit I4, the work pieces within the car I6 are quenched. This entire passage of the elevator from the heattreating oven I2 to the quenching pit I4 takes place in an extremely rapid manner, and occupies a period less than the three or four second period within which the crystalline structure of certain metals or metal alloys changes seriously. If the elevator I5 is halted at its intermediate position in the spray booth I3 (Fig. 2) and if the work pieces within the car I6 are sufficiently insensitive, the car I6 may be run out of the elevator I5 and unloaded at the iioor level I I. If the elevator I5 and car I5 have been quenched.

in the pit I4, however, the elevator I5 is raised to the level of the floor II by operating the cylin- 1 and 2). During this time the doors 34 are in their closed positions so as to conserve heat.

Pressure fluid is now. supplied to the conduit |03 (Fig. 4) forcing the piston |06 to the right and pulling the cable |0I in a direction adapted to rotate the drum |00, shaft 05 and pulley 05 in a clockwise direction (Fig. 2) raising the elevator I5. As the elevator rises, it operates limit switches which energize an electrical circuit to operate magnetic valves which in turn supply pressure iiuid to the conduits 44. This moves the pistons 42 and piston rods 4I outward, opening the doors 34 just in time for the passage of the elevator I5. After the elevator I5 passes the level of the doors 34 it operates other limit switches which actuate magnetic valves for admitting pressure iiuid to the conduits 45l and discharging it from the conduits 44 causing the pistons 42 and piston rods 4| to move inward, closing the doors 34 immediately after the passage of the elevator I5. The latter then actuates other limit switches which shift the magnetic valve controlling the cylinder |01 so as to halt the elevator 1 I5 in the solid-line position of Fig. 2.

The elevator I5 remains within the chamber 32 of the oven I2 for a predetermined length of time, depending upon the nature ofthe work pieces and the materials from which they are constructed. After the heat treatment has been completed, -the electrical circuit is energized to operate the magnetic valves which control the door-actuating cylinders 43 and the elevatoractuating cylinder |01, causing the doors 34 to open momentarily and likewise causing the elevator I5 to be lowered rapidly through the spraybooth I3 into the quenching pit I4. After the elevator I5 passes the level of; the doors 34, the

der |01. The car I6 may then be run out of the elevator I5 and unloaded.

While a specific embodiment of the invention has been described and illustrated, it will be understood that various modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

What I claim isn 1. In a rapid-quench heat-treating apparatus, an oven having an aperture at the bottom thereof. heating means located in vertical passageways on each side of said oven, a quenching device dispcsed below said aperture, an elevator movab e vertically through said aperture between e interior of said ovenand said quenching device, means for moving said elevator, and means for circulating air upwardly past said heater and downwardly through the interior of said oven whereby the heated air will not pass in juxtaposition to the aperture during the initial portion of its ow.

2. In a rapid-quench heat-treating apparatus, an oven having an aperture at the bottom thereof, heating means located in vertical air passageways on each side of said oven, a quenching device disposed lbelow said aperture, an elevator movable vertically through said aperture between the interior of said oven and said quenching device, means for moving said elevator. and means for circulating air upward past said heater and downward through the interior of said oven whereby the heated air will not pass directly to the area of said aperture before traversing said oven chamber.

3. In a rapid-quench heat-treating apparatus, an oven having an aperture in the lower wall,v a

' heater in said oven.- a liquid spraying device disposed beneath said aperture, an elevator movable vertically between said spraying device and the interior of said oven, means for moving said elevator, and a shiftable closure movable into and out of closing relationship relatively to said latter are closed automatically by the shifting v As the elevator I5 passes through the spray" booth I3 it may be subjected to a spray of cooling liquid from the spray pipes I|1 and it may aperture certain portions of said spraying device being mounted on the underside of said closure and movable therewith to direc in the direction of the bath. t a spray fi. In a rapid-quench heat-treating apparatus, an oven having an aperture in its lower wall, a heater in said oven, a liquid spraying device disposed beneath said aperture. an elevator movable vertically between said spraying device and the interior of said oven, means for moving said elevator, a shiftable closure movable into and out of closing relationship` relatively to said aper- `ture, certainportions of said spraying device. be-m ing'supported and movable with said closure andy means operable: in timed relationship with said elevator fory opening said closureduring the pas--V sage otsaid elevator through said aperture and for closing the same when said elevator is inside or outside of said oven whereby vapors from the spraying device will be excluded from said oven.

5. Inl a rapid-quench heat-treating apparatus, an oven having an aperture in the lower portion thereof, a closure for said aperture, a heater in said oven, a` plunge-quenching bath disposed beneath said aperture, an elevator movable. vertically between said bath-and the interior of said I oven, means for moving said elevator, and means for moving said closure in timed relation with said elevator, a spraying device disposed between said oven and said plunge-quenching bath certain .portions of said spraying device being sup? ported and carried by the closure to direct a downward. spray in the direction of the quench-` ing bath.

l6. In a rapid-quench heat-treating apparatus, an' oven having an aperture in the lower porltion thereof, a closure for said aperture, al heater 'in saidA oven, aplunge-quenching bath disposed .beneath said aperture, an elevator movable ver,

tically between said bath andthe interior of said oven, means for moving said elevator in timed relation with said closure, a spraying device. disposed. between said oven and said plunge-quenching bath, certain portions of said spraying: de vice being carried bythe closure for directing a sprayA toward the -bath and loadingand unloading stations adiacenti said: spraying devicev and.

n between the oven and quenchingv bath.

'7. In a.. rapid-quench"heatltreating apparatus,..

an oven having an aperture in the lower' portion thereof, av heater in said'. oven, a plunge-quenching; bath disposed beneath'said aperture, anv ele-A l vator movable vertically between said bath and the interior of said ovenf; meansv :forv moving said' elevatonin timed relation to the sluiting movement of saidA closure',v a spraying device disposed between said oven 'and said plunge-quenchingy bath, a shiftable closure movable into andl out A tically between said bath and the interior of said.

oven, means for moving said elevator, a spraying` device disposed between said: oven and said plunge-quenchingv bath, and means operable in timed relationship with said elevator. for opening said closure during the passage of. saidA elevator: through said aperture and for closing the same, when said 'elevator is inside or outstde of vsaid oven certain portions of saidl spraying device being supported by said closure and movable there-` with. s v

vsaNm A. Foxr 

